/**
 * @license
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
(function() {
  'use strict';

  Polymer({
    is: 'gr-diff-mode-selector',
    _legacyUndefinedCheck: true,

    properties: {
      mode: {
        type: String,
        notify: true,
      },

      /**
       * If set to true, the user's preference will be updated every time a
       * button is tapped. Don't set to true if there is no user.
       */
      saveOnChange: {
        type: Boolean,
        value: false,
      },

      /** @type {?} */
      _VIEW_MODES: {
        type: Object,
        readOnly: true,
        value: {
          SIDE_BY_SIDE: 'SIDE_BY_SIDE',
          UNIFIED: 'UNIFIED_DIFF',
        },
      },
    },

    /**
     * Set the mode. If save on change is enabled also update the preference.
     */
    setMode(newMode) {
      if (this.saveOnChange && this.mode && this.mode !== newMode) {
        this.$.restAPI.savePreferences({diff_view: newMode});
      }
      this.mode = newMode;
    },

    _computeSelectedClass(diffViewMode, buttonViewMode) {
      return buttonViewMode === diffViewMode ? 'selected' : '';
    },

    _handleSideBySideTap() {
      this.setMode(this._VIEW_MODES.SIDE_BY_SIDE);
    },

    _handleUnifiedTap() {
      this.setMode(this._VIEW_MODES.UNIFIED);
    },
  });
})();
